Example embodiments of the inventive concept relate to an optical transceiver module, and in particular, to structures for connecting trace lines of printed circuit boards and optical transceiver modules with the same.
With the widespread usage of internet and media contents, there is an increasing interest on optical transmission/reception systems capable of transmitting a large capacity of voice and video signals at high speed. Conventionally, in 10 Gbps optical transmitter/receiver modules applied for the high-speed optical transmission/reception system, a flexible printed circuit board (PCB) is used outside of an optical module package to transmit high frequency RF signals. The flexible PCB is electrically connected to other PCB for operating the optical transmitter/receiver module. Most of transmission lines on the flexible PCB are configured to have a ground electrode provided below a signal electrode or be a grounded coplanar waveguide (GCPW) type.
When the transmission lines on the flexible PCB are connected to soldering pads of a PCB, a lower electrode of the flexible PCB is partially removed at a position of the soldering pad and be configured to have a CPW structure that via holes are formed in a signal electrode. Since a lower ground electrode is not used to connect the flexible PCB with the PCB, the soldering pad of the flexible PCB may have an increased inductance, and thus, high frequency signals may be seriously reflected by characteristic impedance mismatch. The reflection of high frequency signals may deteriorate transmission quality of optical signals.